Gain enhancement for circularly polarized microstrip patch antenna

Abstract

A method to enhance gain of a circularly polarized (CP) microstrip patch antenna is proposed. We etch coupled square-shaped split ring resonators (CSSSRRs) on both sides of a superstrate which is separated from the patch by an air layer. Thickness of the air layer is around 0.1λ, which keeps the radome in low profile. Open gaps of each CSSSRR on opposite sides of the superstrate are orthogonally oriented to each other. This unique orientation allows the radome not only enhance gain but also maintain good CP performance.